Engine cooling system and apparatus



Au .17,194s. BAY 2,446,995

ENGINE COOLING SYSTEM AND APPARATUS I WATER HEAT EXCH. )2

ENGINE p v 20 y T LUBRICATING on.

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:llWQ/YM THOMAS J. BAY FIG 2 Aug. 17, 1948. T. J. B'AY nuemn cooLIuG 'sYsw Em' Ann Arrhnmus 3 Sheets-Sheet 2- Filed Oct. :51, 1945 Qwumflm THOMAS J. BAY

(Manua Au 17, 1948. T. J. BAY 2, ,9

I ENGINE COOLING SYSTEM AND APPARATUS k Filed Oct. 31. 1945 v s sums-she s TH MAS J. BAY 'lii a O mWL- ' a portion of. the same.

Patented Aug. 17,

2,446,995 ENGINE coonING srs'rEM AND APPARATUS Thomas J. my, United States Navy Application October 31, 1945, Serial No 625,928.

4 Claims.

(Granted under the act of March 3,1883, as amended April 30, 1928; 370 0. G. 757) This invention relates to cooling systems for internal combustion engines and to apparatus for use in such systems, and particularly to systems of the type disclosed in my Patent No. 2,365,166

. granted December 19, 1944. The principal objects of the present invention are to provide apparatus for use in systems like those disclosed in that patent and in this specification, and also to provide a system improved in certain respects over the earlier one.

The system disclosed in'Patent No. 2,365,166 constituted improvements in internal combustion engine cooling wherein the engine cooling water after having passed in heat exchange relation with a prime cooling medium is then passed in heat exchange relation with the lubricating oil or Among the objects of that invention were provision of means for controlling the cooling water temperature and for controlling the temperature of the lubricating oil. One desirable possibility in such a system is to provide for the rapid elevation of temperature of both the water and the lubricating oil on starting the cold engine. This serves to minimize engine wear, render the installation more reliable in service and reduce expense of maintenance.

While the system provided in the above mentioned prior patent has given good service and in many applications is very satisfactory, I have in the present instance devised an improvement on that system particularly valuable to provide for bringing the lubricating oil to proper operating temperature as rapidly as possible after starting a cold engine and to provide forclose control of lubricating oil temperature in cases where the engine design provides for relatively large rise in lubricating oil temperature during its circulation through the engine. I have further devised improved apparatus for use in the new system aswell as in the system previously disclosed.

With the object of clearly disclosing the invention, the accompanying drawings will be discussed in connection with the description as pre senting preferred embodiments from which numerous departures may be made within the scope of the invention.

Figure 1 is a representation of a complete system for controlling the temperatures of water and of lubricating oil for an internal combustion engine.

Figure 2 shows a heat exchanger with a pre- Figure 4 shows a' further form of heat exchanger involving sectional structure and a plurality of valves.

In Figure 1 the major elements of the-engine cooling system comprise the internal combustion engine I, water heat exchanger 2 and oil heat exchanger 3. The engine heat exchange medium leaves the water jacket by pipe 4 and returns through pipe 5. The entire flow or any portion of the circulating lubricating oil is taken from any suitable point in the lubricating system at 6 and returned at 1.

Both heat exchangers are represented as being of the type in which two fluids are passed in heat exchange relation with each other but without mixture of the two fluids. -In order to convey this idea the two fluids are shown as passing through separate coils within the exchangers. Thus in exchanger 2 the primary cooling medium passes through coil 8, and the engine jacket water through coil 9, and in the oil heat exchanger 3 water passesthrough coil 10 while the lubricating oil flows in coil l I.

gine, while the thermostatic element 20 of valve The various elements of the piping represented for conveying the several fluids involve a section l3 to the water heat exchanger, a section 14 between the-two heat exchangers, a portion l 5 from 5. Valves l1 and [9 are thermostatically controlled valves. hereinafter fully described. In the case of valve I! the control element I8 is ln'thermal relationship with the water leaving the enl9, though the valve controls water circulation, is in thermal relation with, and controlled by the temperature of, the oil leaving heat exchanger 3.

Figure 1 is diagrammatic in nature and does not, save in a general manner, indicate the construction of the various elements. While it appears that external pipes and valves are employed, this is not necessarily true, as will appear later from description of my newly devised heat exchanger. The description willproceed by setting forth the system as applied to a marine engine installation wherein sea water constitutes the prime heat exchanger medium flowing in coil ferred form of thermostatic valve incorporated in its structure.

Figure 3 shows a heat exchanger with a modifled form of valve.

-. exchangers and return to the engine.

the oil is cooled to too low a temperature, valve l9 will open partially, allowing some of the hot direction of the arrows at pipes 4 and 5. The water is forced to flow through pipe I5 since the valve I1 is closed to flow there through by operation 01' its thermostatic element l8. For purposes of this diagrammatic presentation, valve I1 is indicated as of a type allowing flow in one-or both of two directions, flow being allowed through l3 and I5 when the water at I8 has reached a predetermined elevated temperature and through IE only at lower temperatures. Valve I9 is of the 34 through tube 33 is allowed at all times.

tended position, will uncover openings 40. ,When

' incoming water is hot'and contract when it is type which I have in my previous patent speciflcation describedas a three-way valve. Its operation is to direct fluid flow in one or the other,

of two directions in this case to pipes 2| or I6 depending upon the temperature of the oil atfecting the element 20. When the thermostat 23 is at a low temperature, action of valve i9 is to send all the water through pipe 2| and thus through coil H] of heat exchanger 3. Therefore, under starting conditions the course of the engine jacket water will be in sequence through pipes 4, l5, valve l9, pipe 2|, coil I0 and pipe 5 back to the engine jacket. The water heat exchanger 2 is completely by-passed, as is evident, and thus the engine water, subjectonly to a minimum cold, it being contemplated that suitable adjustments may be provided in known manner. The element may be of any of the bellows, bimetallic or other type.

As applied in the system according to Figure 1, the space within the shell corresponds to coil 8. The assembly of tubes 32 corresponds to coil 9, the thermostat valve to valve I'I, tube 33 to by-pass pipe l5, and element 39 to element Hi.

In operation sea water will circulate through the shell around the tubes. Upon starting the engine, cold water from the engine will enter inlet 34, from pipe 4 of Figure 1, and pass directly through valve housing 31, valve 38, and by-pass tube 33, the downstream end of which is conamount of heat radiation, will have its temperaheat passes into the cooling water than passes into the lubricating oil, it will be seen that the heat exchange relationship between the rapidly heating water and the oil in exchanger 3 will serve to increase the temperature of the cold oil rapidly, which is one of the main objects of the system. When the oil is at proper operating temperature, valve l9 will act to control the amount of water passing through Hi from the engine. When full operating conditions have been reached all the cooled water from heat exchanger 2 will pass through heat exchanger 3, while part of the water will by-pass both heat In case water from valve i! to pass by pipe 2| to the 01] heat exchanger 3. In this manner a very close control of the lubricating oil temperature is possible. This is of especial benefit in connection with engines using a small quantity of oil which may have to absorb a great deal of heat at high power operation of the engine.

Figure 2 indicates a heat exchanger containing the essential elements for constituting the water heat exchanger 2 shown in the diagram of Figure 1. This heat exchanger comprises a cylindrical shell 25, water chests 26 and 21 at either end of the shell and a tube assembly comprising headers or tube sheets and 3| and tubes 32. Inlet 28 and outlet 29 are provided for the fluid which will flow exteriorly of the tubes 30 and 3|, in the case,here described, said fluid being sea water. In-addition to the heat exchanger tubes, there is provided a by-pass tube 33 also secured in the tube sheets 30 and 3|. Water inlet 34 is provided in the water chest 26 and an outlet 35 in water chest 21. As an integral portion of the inlet 34, there is an extension constituting a valve body 3! having openings in its sides. Avalve closure 38, operated by a thermostatic element 39, serves to control flow through the openings 40 and, indirectly, through the by-pass tube 33. As will be apparent from the drawing, valve closure 38, when in its exnected to tube l5 of Figure 1. Since the water is cold, thermostat 39 is contracted and ports 40 in valve housing 31 are closed by valve 38 so all the water coming from the engine must pass into tube l5 of Figure 1 which conveys it to three-way thermostatic valve IQ of Figure 1. Since the lubricating oil circulating through tube 1 from the oil heat exchanger 3 is also cold when the engine is started, the thermostat bulb 20 in thermal contact with the cold oil in pipe 1 causes three-way valve l9 to divert the entire quantity of water entering it from tube Hi to tube 2|, allowing none of it to pass into tube l6. Thus the flow of jacket water when the cold engine is first started is as follows: through pipe 4 to valve 34, to by-pass tube 33, to tube I5, through valve Hi to pipe 2|, through the jacket water circuit of the oil heat exchanger 3, and back to the engine through tube 5.

Since the cooling tubes of the water heat exchanger are being by-passed, the heat absorbed by the jacket water in the engine is not being dissipated and the jacket water rapidly increases toward the desired operating range. When it reaches the desired temperature the thermostat 39 extends, gradually opening ports 40 in valve housing 31 and permitting sufficient jacket water flow through the cooling tubes 32 for coolin as necessary to maintain a constant temperature of the jacket water passing from the engine through tube 4. This cooled water is discharged from tube 32 into water chest 21, and thence out of the water heat exchanger through outlet 35.

and into tube ll of Figure 1. I

It will be noted that jacket water is not admitted to cooling tubes 32 until its temperature leaving the engine has been elevated to operating range. Prior to this time, all the heat absorbed by the jacket water flowing through the engine is available for heating the lubricating oil in oil heat exchanger 3. In this way the lubricating oil is rapidly heated to the desired operating range. When the lubricating oil approaches the desired temperature, thermostat bulb 20 actuates three-way valve l9 and causes a division of flow oi! jacket water at this point, i. e., part of the hot Jacket water is permitted to circulate directly back to the engine through pipe 5 and the remainder continues to flow through pipes 2| and Since the lubricating oil is heated more slowly than the jacket water when the engine is started, by the time hot jacket water is permitted by valve l9 to flow through pipe 2|, cooled jacket water from the jacket water heat exchanger is flowing through pipe I4 into which tube 2| discharges, and under this intermediate condition a mixture of hot and cooled jacket water flows into the oil heat exchanger.

We may now consider the conditions obtaining when the engine has been operating for some time and temperature conditions have stabilized. Valve I1 is now dividing the flow of jacket water so as to maintain a constant temperature of the jacket water leaving the engine. Valve I9 is dividing the flow of hot jacket water, entering it from tube l5, between tubes 2| and IB. Just suiilcient flow of hot water is permitted through tube M to dilute the cooled water coming from the water heat exchanger as necessary to keep the lubricating oil, flowing to'the engine from the oil heat exchanger through pipe I' at the desired operating temperature. The balance of the hot jacket water flowing into valve l9 from tube l5 passes through tube l6 and combines with the jacket water issuing from the oil heat exchanger in pipe 5. Thus, by proper initial adjustment of thermostatic valves l1 and |9,'the temperature of the jacket water leaving the engine and the temperature of the lubricating oil entering the engine are both automatically maintained within the desired operating range, and at the same time the temperature of the jacket water entering the engine can be reheated to a temperature approaching or even higher than the temperature of the lubricating oil entering the engine;

ters are used, except for the valve closure which is referred to as 48 since it is difl'erent from the valve closure 38. The action of this valve is somewhat different from that of Figure 2 in that positive cut-off occurs in both positions. This form of valve is capable of closing communication with by-pass tube 33. In operation of this device, cold water entering inlet 34 will pass through openings 49 and by-pass 33; When the water has warmed sufiiciently action of the element 39 will uncover openings 40 allowing an increasing portion of the water to pass through tubes 32, water chest 21, and outlet 35. When the valve is entirely extended, no water is bypassed. A further difference is that by-pass 33 discharges into water chest 21, rather than having a separate outlet.

Figure 4 represents a modified type of heat exchanger for use either with an oil or water systern, and comprising a plurality of thermostat controlled valves. Reference characters are applied to the same elements involved in the con struction of Figure 3. Major difierences involved comprise dividing the tube assemblies by providin a plurality of by-pass tubes 33 with their associated thermostat valves. Action of the valves will be identical with that heretofore described. Provision of the plurality of valves entails a number of advantages, prominent among which are use of standard sizes of valves for various sizes of heat exchanger, andpossibility of satisfactory operation, even though one or more of the valves should fail. It is contemplated that the valves will be so constructed that upon failure they will act to open communication with the tubes 32 in order to utilize the full heat exchange capacity of the system. The valves may be of the type shown in Figure 2.

In the heat exchangers described above, the by-pass is as shown in order to secure the ad- 6 vantages of integral construction of the valve. Negligible heat exchange will occur due to the v relatively small surfaces exposed.

It is believed that advantages not specifically referred to-wili be obvious, as will modifications 10 not departing from the scope of the appended claims. e

s The invention described herein may be made and used by or for the Government of the United States for governmental purposes without the payment to me of any royalties thereon or therefor. WhatI claim is: a

1. A system for controlling the temperatures of the cooling water and of the lubricating oil for an internal combustion engine wherein a first heat exchanger cools the water flowing from the engine and a second heat .exchanger controls the temperature or the lubricating oil; characterized by the fact that there is combined with said first heat exchanger means for by-passing a portion of the heated water from the engine around said first heat exchanger for alternative delivery to said second heat exchanger or directly to the engine, and means for determining the portions of said by-passed heated water which are to be delivered to the second heat exchanger and directly to the engine.

2. .A system for controlling the temperatures of the cooling water and of the lubricating oil for an internal combustion engine wherein a first heat exchanger cools the water flowing from the engine and a second heat exchanger controls the temperature of the lubricating oil; characterized by the fact that there is combined with said first heat exchanger means controlled by the water temperature 'for by-passing a, portion or the heated water from the engine around said first heat exchanger for alternative delivery to said secondheat exchanger or directly to the engine, and means for determining the portions of said by-passed heated water which are to be delivered to the second heat exchanger and directly to the engine.

3. A system for controlling the temperatures of the cooling water and of the lubricating oil for an internal combustion engine wherein a. first heat exchanger cools the water flowing from the engine and a second heat exchanger controls the temperature of the lubricating oil; characterized by the fact that there is combined with said first heat exchanger means for bypassing a. portion of the heated water from the engine around said first heat exchanger for alternative delivery to said second heat exchanger or directly to the engine. and means controlled by the temperature of the lubricating oil for determining the portions of said by-passed heated water which are to be delivered to the second heat exchanger and directly to the engine.

4. A system for controlling the temperature of the cooling water and of the lubricating oil for an internal combustion engine wherein a first heat exchanger cools the water flowing from the engine and a second heat exchanger controls the temperature of the lubricating oil; characterized by the fact that there is combined with said first heat exchanger means controlled by the water temperature for by-passing a portion of the heated water from the engine around said first heat exchanger for alternative delivery to said second '7 8 heat exchanger or directly to the 0881115; .1111! UNITED S'I'A'I'ES PATENTS means controlied by the temperature or e ubricating oil for determining the portions of said 33? Name Oct a by-passed heated water which are to be delivered 1:934'496 N 1933 to the second heat exchanger 'and directly to the I 3291'? 1 2 1942 engine mom 3 1 B8! Dec. 19: 1944 .7 Qhindler Jan, 8, 1946 REFERENCES CITED 2,417,287 Qhahdier Mar. 11, 1947 The following references are of record in the 19 tile of this patent: 

